JPH09324643A - Exhaust system structure of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spacer which serves as an exhaust connection pipe between an exhaust port formed on an upper end of an exhaust manifold and an inlet port of a supercharger to enable to correspond to an attachment of any supercharger by changing an attachment direction of the spacer. SOLUTION: A spacer 2 is provided between an inlet end of a turbine of superchargers T1 and T2 and exhaust port of an exhaust manifold 1. Furthermore, in a case where a sequential control system is adopted wherein a state in which both superchargers T1 and T2 are operated and a state in which only one of the superchargers T1 and T2 is operated are changed over, an exhaust control valve is provided only on one of both spacers 2 and 2. Furthermore, weld assemblage type water cooling style exhaust manifold is constituted wherein the exhaust pipes are covered with outside covers.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an exhaust system structure of an internal combustion engine.

[0002]

2. Description of the Related Art In response to the demand for exhaust emission reduction, in order to improve the efficiency of supply air pressure, cylinders are divided into two groups and are independently connected to an exhaust manifold, or all cylinders are connected to each other. By communicating with the exhaust manifold, two exhaust outlets are formed in the exhaust manifold, each exhaust outlet is connected to an independent supercharger, and from both superchargers,
BACKGROUND ART An internal combustion engine that supplies air to a multi-cylinder air supply pipe to improve air supply efficiency has been known. Among them, it is publicly known that the exhaust outlets of two superchargers are opposed to each other and merged into one exhaust bend to achieve compactness. Furthermore, in order to adjust the exhaust gas supply pressure to the supercharger, it has been conventionally known that the turbine portion of the supercharger is provided with a waste gate passage (with a switching valve) for directly feeding the excessive exhaust gas to the exhaust bend. Has become.

Further, in the internal combustion engine, it is also known to employ a sequential control system in which only one supercharger is operated at low load and both superchargers are operated at high load. There is. At low load, only one supercharger can secure sufficient air supply pressure, and if two units are operating, output loss will occur rather, so exhaust introduction to one unit will be stopped and operation will be stopped. Of.

Further, the exhaust manifold may be a water-cooled type because the exhaust temperature rises due to higher engine output. The conventional water-cooled exhaust manifold has an exhaust passage interposed between the cylinder head and the supercharger, and has a complicated structure covered with an external cover to form a cooling water chamber so as to surround it. Therefore, these were integrally formed by casting.

[0005]

In the conventional internal combustion engine, each supercharger has a structure in which it is directly attached to the outlet end of the exhaust manifold, and the outlet end of the exhaust manifold itself is attached to the supercharger. Had to be processed into. In the case of the twin turbo type, even if two turbochargers are similarly provided, if the exhaust outlets of both turbochargers face each other in order to achieve compactness, both turbochargers will be installed in opposite directions. Therefore, the mounting portions of the exhaust manifolds of the respective groups to the supercharger cannot be dealt with unless they have different shapes. In other words, the exhaust manifold has a complicated shape, and since the shapes of the exhaust manifolds of both groups cannot be unified, the processing cost becomes high.

Further, as described above, the wastegate passage is conventionally built in the turbine portion of the supercharger, but if both passages are built in, the wastegate passage may have a valve structure. , The cost will be higher. On the other hand, if the passage is built in only one supercharger, the operating balance of both superchargers will be lost.

In an internal combustion engine which employs a sequential control system, when only one supercharger is operated, it is brought into an operation stop state at the inlet portion of the supercharger, and the exhaust manifold is operated. An exhaust control valve must be provided to stop the exhaust inflow. Conventionally, the outlet of the exhaust manifold forms a mounting portion to the supercharger, which complicates the shape, and when such a valve structure is provided,
Further, the shape becomes complicated, which hinders downsizing and cost reduction.

Further, since the conventional water-cooled exhaust manifold has a complicated structure as described above, an integral structure of a casting mold is generally used. However, since a complicated mold such as a core is required, the production quantity is increased. If the amount is small, there is also a heavy burden of depreciating the mold, which is a factor that hinders cost reduction.

[0009]

The present invention uses the following means to solve the above problems. First of all, the internal combustion engine has a structure in which two outlets are formed in the exhaust manifold, and each outlet is connected to two independent superchargers, and the rotation shafts of both superchargers are the longitudinal direction of the exhaust manifold. In a structure in which both turbochargers are located above the exhaust manifold so that the exhaust outlets of both superchargers face each other, the exhaust outlet formed at the upper end of the exhaust manifold and the supercharger inlet A spacer, which also serves as an exhaust communication pipe, is provided therebetween, and the spacer can be mounted to any supercharger by changing the mounting direction.

Secondly, there is an internal combustion engine having a structure in which two outlets are formed in the exhaust manifold, and the two outlets are connected to two independent superchargers, and the rotating shafts of both the superchargers are of the exhaust manifold. In a structure that is parallel to the longitudinal direction and has the exhaust outlets of both turbochargers facing each other, and that both superchargers are placed above the exhaust manifold and both exhaust outlets are connected to one exhaust bend, A waste gate passage separate from the supercharger is provided from the manifold to the exhaust bend.

Thirdly, the internal combustion engine having the structure described in the first paragraph adopts a control system capable of switching between a state in which only one supercharger is operated and a state in which both superchargers are operated. The exhaust control valve is installed only in one of the two spacers to which each supercharger is attached.

Fourthly, the exhaust passage provided between the cylinder head of the internal combustion engine and the supercharger is covered with an external cover,
A water-cooled exhaust manifold having a space between the outer cover and the exhaust passage as a cooling water chamber, wherein the outer cover and the exhaust passage are separate bodies, and the exhaust passage is a separate exhaust introduction pipe. , The exhaust branch pipe, and the exhaust merging pipe are connected to each other, and each connection part is provided with a water-cooled exhaust manifold constructed by welding to maintain water tightness.

[0013]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a supercharger T1 via a spacer 2.
-Exhaust manifold 1 of internal combustion engine with T2 attached structure
FIG. 2 is a partial cross-sectional view of the front surface of the piping portion, FIG. 2 is a partial cross-sectional view of the same side portion of the turbocharger T1 as seen from the left in FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view of the side view seen from the left side, FIG. 4 is a partial cross-sectional front view of the exhaust manifold 1 piping portion of the internal combustion engine having a structure in which the waste gate pipe 9 is provided, and FIG. 5 is a structure in which the waste gate pipe 9 ′ is provided. FIG. 6 is a partial side sectional view of the exhaust manifold 1 piping portion of the internal combustion engine of FIG.
Having an exhaust manifold 1 of a type for supplying to the supercharger T
2 is a partial sectional front view of the exhaust manifold 1 piping portion of the internal combustion engine of the sequential control system in which 2 can be stopped, and FIG. 7 is a partial side sectional view of the turbocharger T2 mounting portion as viewed from the left side in FIG. FIG. 8 is an exhaust / air supply system diagram in the structure shown in FIGS. 6 and 7, and FIG. 9 is an exhaust manifold 1 of a type in which the inside is divided into two and the exhaust is independently supplied to both superchargers T1 and T2. 11 is a partial cross-sectional front view of the exhaust manifold 1 piping portion of the internal combustion engine of the sequential control system that has the turbocharger T2 that can be stopped, and FIG. 10 is an exhaust / air supply system diagram in the structure shown in FIG. Is a partial plan view in section showing a water-cooled exhaust manifold 1'having a welded assembly structure, and FIG. 12 is a partial sectional view in plan view showing a water-cooled exhaust manifold 1 "having a welded assembly structure.

First, it is assumed that the internal combustion engine (engine) according to the embodiment shown in FIGS. 1 to 12 is a 6-cylinder engine. First, the structure of the exhaust manifold will be described. As shown in FIG. 1 and the like, the exhaust manifold 1 is mounted and arranged on the front surface of the cylinder head CH, and is also separately mounted on the front surface of the cylinder block CB through the support members 8 and 8. . An air supply connecting pipe 6 is provided above the exhaust manifold 1 in parallel with the longitudinal direction of the exhaust manifold 1.
The exhaust manifold 1 is supported by support members 7. Further, the exhaust manifolds 1 ′ and 1 ″ described later are also mounted and supported in the same manner as the exhaust manifold 1 shown in FIG.

The exhaust manifold shown in FIGS. 1 to 12 in the present embodiment is a water-cooled type, but the exhaust manifold 1 shown in FIGS. 1 to 10 has an integral casting structure, and the exhaust manifold 1 shown in FIGS. 1 is a welded assembly structure. First, the former water-cooled exhaust manifold 1 of the integrally cast structure shown in FIGS.1 to 10 will be explained.The inside is an exhaust main pipe 1b as shown in FIGS. (1b '・ 1
b ′) is covered with an outer cover 1a, and the space between the outer cover 1a and the exhaust main pipe 1b (1b ′ · 1b ′) is a cooling water chamber. On the inner surface of the outer cover 1a, a total of six exhaust introduction pipes 1c, 1c ... Are provided so as to communicate with the exhaust passage formed in the cylinder head CH of each cylinder. Exhaust outlets 1d and 1d are formed on the upper surface thereof so as to communicate with the respective superchargers T (spacer 2 described later). Further, the outer cover 1a is provided with inlets and outlets of cooling water, and as shown in FIGS. 1 and 2, the cooling water pipes WP and WP for supplying and discharging the cooling water in the cooling water chamber are provided with the respective openings. Connected to.

As described above, a total of six exhaust gas introducing pipes 1c, 1c ... Are extended from the inner surface of the outer cover 1a to the cylinder head CH of each cylinder. As shown in FIG. 9, a single connected exhaust main pipe 1b communicating with all the exhaust introduction pipes 1c, 1c ...
Some have two main exhaust pipes 1b ', 1b' communicating with the three left and right exhaust introduction pipes 1c, 1c, 1c.
Exhaust outlet 1d for discharging the exhaust gas to the turbochargers T1 and T2 described later
In the former structure shown in FIGS. 4 and 6, 1d is formed on the left and right portions of the upper end of the exhaust main pipe 1b, while in the latter structure shown in FIG. 9, it is formed at the upper end of each exhaust main pipe 1b ′ · 1b ′. It is formed. Therefore, the former is, as shown in FIG. 8, all cylinders C1 to C6.
Exhaust gas from C1 to C3 is introduced into both superchargers T1 and T2, and the latter exhausts from cylinders C1 to C3 and C4 to C6 independently as shown in FIG. It has a structure to be introduced into the superchargers T1 and T2. In the latter structure shown in FIGS. 9 and 10, both turbochargers T
A communication passage (R in FIG. 10) for communicating exhaust gas from each of the exhaust main pipes 1b ′ and 1b ′ is provided at the inlet of 1 · T2 so that only one supercharger described later can be operated. ing.

The exhaust manifold 1 shown in FIGS. 1 to 10 has an outer cover 1a, an exhaust main pipe 1b or 1.
The b ', the exhaust introduction pipe 1c, and the exhaust outlet 1d are integrally formed by an integral casting die.

Next, the water-cooled exhaust manifolds 1'and 1 "of the welded assembly type structure shown in Fig. 11 and Fig. 12 will be described. First of all, from the cylinder head CH to the supercharger T (a spacer 2 described later). The outer cover 18 (18 ′) covers the exhaust passage provided between the outer cover 18 (1 ′) and the space between the two to form a cooling water chamber.
Six exhaust introduction pipes 19 and 19 '(4 exhaust introduction pipes 19 and two exhaust introduction pipes 19') are projected from the inner surface of 8 ') to the cylinder head. In the exhaust passage in the outer cover 18 of the exhaust manifold 1 ′ shown in FIG. 11, the outer end of the exhaust branch pipe 20 is welded to the inner end of the exhaust introduction pipe 19, and the exhaust branch pipe 20 is connected to the exhaust merge pipe 21. The other end is welded to the inner end of the exhaust gas introducing pipe 19 '. (The exhaust introduction pipe 19 ′ is directly welded to the exhaust merging pipe 21 without the exhaust branch pipe 20). The exhaust manifold 1'includes three exhaust introduction pipes 19 / 19.1.
9'includes two exhaust merging pipes 21. Therefore, in the exhaust system structure shown in FIG. 10, two superchargers TT are independently exhausted from each exhaust merging pipe 21. It has a structure that can supply.

Next, the exhaust passage in the outer cover 18 'of the exhaust manifold 1 "shown in FIG. 12 is located at the inner end of the exhaust introduction pipe 19 among the exhaust introduction pipes 19 and 19' communicating with each cylinder head CH. The outer ends of the exhaust branch pipes 20 'are welded, and the inner ends of the two exhaust branch pipes 20' and the inner ends of the two exhaust introduction pipes 19 'are welded to one exhaust merge pipe 21'. The exhaust manifold 1 ″ includes all of the six exhaust introduction pipes 19 and 19 ′ as one exhaust merging pipe 21 ′.
Although only one outlet flange portion 21'a of the exhaust merging pipe 21 'is formed, exhaust gas is supplied to one supercharger T. Of course, two outlet flange portions 21'a may be formed in the exhaust merging pipe 21 ', and in this case, the exhaust supply structure shown in FIG. 8 is obtained.

Further, in the exhaust manifold 1 '(1 "), the outer cover 18 (18") and each exhaust introduction pipe 19,
19 ', and the outer cover 18 (18'),
Spacer 2 to be described later formed on the upper end of the exhaust merging pipe 21 (21 ').
It is also welded to the outlet flange portion 21a (21'a) for connection to. Watertightness is maintained at each of the above welding points.

In the following embodiments, the exhaust manifold 1 is not only the integrally cast type exhaust manifold 1 shown in FIGS. 1 to 10, but also the welded assembly type exhaust manifold 1'shown in FIG. Can be replaced by As described above, if two outlet flange portions 21'a are provided, as shown in FIG.
The illustrated exhaust manifold 1 "is also applicable (a structure with two outlet flanges 21 'is provided for the exhaust manifold 1".
Let it be α. )

The mounting structure of the supercharger will be described with reference to FIGS. 1 to 3. Two turbochargers T1 and T2 are used to form a twin turbo engine, but both turbochargers T
1 and T2 are the same, and the mounting direction is simply reversed so that their exhaust outlets face each other.
Each turbocharger T1 and T2 has a turbine T and a blower B, respectively.
And the turbine T has its inlet end Ta.
The exhaust outlet 1 that opens to the left and right of the upper end of the exhaust manifold 1.
Connect to d-1d. The exhaust gas introduced from the exhaust manifold 1 is compressed by the turbine T, and the surplus exhaust gas is exhausted via the exhaust outlet pipe 3 and the exhaust bend 4 provided between the exhaust outlet pipes 3 and 3. The lower portion of the exhaust bend 4 is supported by the support member 5 on the upper surface of the exhaust manifold 1. On the other hand, the blower B introduces the intake air from the outside through the outside air introduction port Ba, and also introduces the exhaust gas compressed by the turbine T and sends them out as the intake air, thereby supplying the above-mentioned intake air. It is sent to the intercooler (supply air cooler) IC via the connecting pipe 6. Further, the supply air is supplied from the intercooler IC to the cylinder head CH of each cylinder.
Is sent to

Like the exhaust manifold 1 shown in FIG. 4, the exhaust manifold 1 shown in FIGS. 1 to 3 is of a type having an exhaust main pipe 1b connected inside (the exhaust manifold 1 ″ α is applicable. Therefore, since the exhaust gas introduced into both the turbochargers T1 and T2 communicates with each other in the exhaust manifold 1, the supercharging without forming the communication passage R in the upper part of the exhaust manifold 1. Machine T1 ・ T
2 will be attached. When the exhaust manifold 1 has independent exhaust main pipes 1b ′ and 1b ′,
The installation structure of the supercharger is different in that the communication passage R is provided. This will be described later in the description of the mounting structure of the exhaust control valve based on FIGS. 9 and 10.

A spacer 2 is provided between the exhaust outlet 1d of the exhaust manifold 1 and the inlet end Ta of the turbine T of the superchargers T1 and T2. The spacer 2 has a tubular structure,
It also serves as an exhaust communication pipe from the exhaust manifold 1 to the turbines T of the turbochargers T1 and T2. Shape is exhaust manifold 1
The vicinity of the lower end, which is a mounting seat for the, is perpendicular to the longitudinal direction of the exhaust manifold 1, and is bent in a dogleg shape in the middle as shown in FIGS. 2 and 3. This is because the turbochargers T1 and T2 are connected to the exhaust outlet pipes 3 and 3 and the exhaust bends 4 are shared so that the rotational axis extension lines of the superchargers T1 and T2 are aligned. That is, the exhaust passage in the turbine T has a spiral shape as shown in FIGS. 2 and 3, and when the front and rear are reversed like the turbochargers T1 and T2, the inlet end Ta thereof is unevenly distributed forward or backward. To do. In the case of the present embodiment, that of the supercharger T1 is rearward as shown in FIG.
It's leaning forward as in Figure 3. Therefore, if the same spacer 2 is turned upside down, the upper end of the spacer 2, which is a mounting seat for the inlet end Ta of the turbine T, is provided as shown in FIG. It will be closer to the rear or closer to the front as shown in FIG. Therefore, in order to make the exhaust outlets of the turbine T face each other, the superchargers T1 and T2, which are mounted by reversing the mounting positions, are installed on the exhaust manifold 1 only by changing the mounting direction of the same spacer 2. It can be attached.

When a supercharger having a different structure is adopted as the supercharger T1 and T2, conventionally, the outlet end of the exhaust manifold 1 has to be changed, so the exhaust manifold itself must be reworked. However, if the structure is such that the spacer 2 is attached via the spacer 2, it can be dealt with by reworking the spacer 2 separate from the exhaust manifold 1, and the cost can be reduced.

Next, the connecting structure between the turbine T of each of the superchargers T1 and T2 and the exhaust outlet end 3 will be described. The inlet end portion of the exhaust outlet pipe 3 is a seal ring portion 3a, and an annular groove is provided at the exhaust outlet end Tb of the turbine T, and the seal ring portion 3a is slidably fitted in the groove. Has become. That is, the exhaust outlet pipe 3 is slidable with respect to the turbine T, which allows the exhaust outlet pipe 3 to be stretched under the influence of high-temperature exhaust gas, and can be extended to the turbine T during stretching. The inner fitting portion of the seal ring portion 3a maintains the sealing property.

Next, a structure having the waste gate passage shown in FIG. 4 will be described. In the present embodiment, the inside of the exhaust manifold 1 has a structure having a continuous exhaust main pipe 1b (the exhaust manifold 1 ″ α can be applied), and both exhaust outlets 1b at the upper end of the exhaust main pipe 1b.・
A waste gate introduction opening 1e is provided below the exhaust bend 4'between 1b. Exhaust bend 4 '
Inside, a waste gate outlet pipe portion 4'a is formed below the confluence portion of the exhaust pipe portions 4'b, 4'b communicating with the exhaust outlet pipes 3, 3 of the superchargers T1, T2. . A waste gate pipe 9 is formed between the waste gate introduction opening 1e and the waste gate outlet pipe portion 4'a so as to form a waste gate passage 9a in a vertically penetrating manner. By providing the waste gate pipe 9, the support member 5 that supports the exhaust bend 4 with respect to the exhaust manifold 1 is not required.

In the waste gate passage 9a,
A wastegate valve 10 is arranged so as to face the wastegate introduction opening 1e of the exhaust manifold 1 at the opening at the lower end thereof. An actuator 11 for driving the wastegate valve 10 is arranged outside the wastegate pipe 9. The actuator 1
Reference numeral 1 connects an air pipe 11a to an air supply connecting pipe 6 (not shown) to introduce the air supply in the air supply connecting pipe 6, and the drive amount is adjusted by this air pressure. On the other hand, the actuator 11 is connected to the switching arm 10a of the wastegate valve 10,
The valve opening amount of the waste gate valve 10 is adjusted based on the driving amount of the. For example, when the supply air pressure becomes higher, the opening amount of the waste gate valve 10 increases, and a large amount of exhaust gas flows into the waste gate passage 9a to reduce the amount of exhaust gas introduced into the superchargers T1 and T2. In this way, the amount of exhaust gas introduced into the superchargers T1 and T2 is adjusted based on the supply pressure, and the supply pressure can be maintained at the set pressure amount.

In the case of FIG. 4, the waste gate introduction opening 1e is arranged at the upper end of the exhaust manifold 1, and the inlet opening of the waste gate outlet pipe 4'a of the exhaust bend 4'is arranged downward. Exhaust manifold 1
Depending on the piping position of the air supply connecting pipe 6 that is piped above
It may have to be offset outwards. In such a case, as shown in FIG. 5, the waste gate introduction opening 1e ′ is opened on the outer side surface of the exhaust manifold 1, and the inlet opening of the waste gate outlet pipe section 4′a is provided outward. , A waste gate pipe 9'bent in a U-shape when viewed from the side is provided between the waste gate introduction opening 1e and the inlet opening of the waste gate outlet pipe portion 4'a so that the exhaust manifold 1 The upper space can be secured.

Next, a twin-turbo engine equipped with the superchargers T1 and T2, which can be switched between a state in which only one supercharger is operated and a state in which both superchargers are operated The arrangement structure of the control valve in the control type will be described with reference to FIGS. 6 to 10. First, FIGS. 6 to 8 show an embodiment in which the inside of the exhaust manifold 1 communicates with the exhaust introduction pipes 1c, 1c ... (6 in total) to all the cylinders, that is, an embodiment having an exhaust main pipe 1b. Is. (For this, the exhaust manifold 1 ″ can be applied.) The turbochargers T1 and T2 have exhaust manifolds via the spacers 2 and 2, respectively, similarly to the structure of FIGS. It is attached to the upper part of 1. The exhaust control valve 12 is arranged only in the spacer 2 to which the supercharger T2 is attached among the spacers 2 and 2. The exhaust control valve 12 is a rotating shaft 12a. 12a is pivotally supported on the side surface of the spacer 2, and the valve opening amount is adjusted at the pivot position. Only the supercharger T1 is operated at a low load. When it is desired to lower the supply pressure, the exhaust control valve 12 is closed and the supercharger T2
The introduction of exhaust gas to the turbine T is stopped. In the supercharger T2 provided with the exhaust control valve 12 at the inlet, when the exhaust control valve 12 is closed and the introduction of exhaust gas is stopped, the exhaust outlet from the blower B to the supply air connecting pipe 6 has a low pressure. Therefore, the supply air sent from the blower B of the supercharger T1 in the operating state flows back to the outlet side of the blower B of the supercharger T2 in the stopped state through the supply air communication pipe 6, and the supply pressure is increased. Is reduced. In order to prevent this, the air supply control valve 13 is provided at the outlet of the turbocharger T1 (the outlet of the blower B) having the exhaust control valve 12 at the inlet as shown in FIG. It has a structure that closes in conjunction with closing the valve. Further, at a position upstream of the air supply control valve 13,
The air supply relief valve 14 is provided to connect the outside air introduction port B of the blower B.
It is configured to return to the a side and has a structure that opens in conjunction with the closing of the air supply control valve 13.

As described above, the exhaust control valve 12 is attached to the spacer 2 instead of being attached to the exhaust manifold 1 itself having a complicated pipe structure, which contributes to cost reduction. It should be noted that the exhaust control valve 12 can be easily removed from the spacer 2, and when it is removed, the exhaust control valve 12 shown in FIGS.
It can be a normal twin-turbo engine, as seen in.

Finally, the arrangement structure of the exhaust control valve of the split twin turbo engine shown in FIGS. 9 and 10 will be described. Also in this case, when only one supercharger is operated, it is the supercharger T2 that is stopped, and in the air supply system on the outlet side of the supercharger T2, the structure shown in FIGS. Similarly to the above, as shown in FIG. 10, an air supply control valve 13 and an air supply relief valve 14 are provided.

In the present embodiment, the exhaust manifold 1 has a structure in which the inside is divided into exhaust main pipes 1b 'and 1b'.
This is because by independently introducing the exhaust gas to each of the superchargers T1 and T2, a pulsation occurs in the introduced exhaust gas of the superchargers T1 and T2, thereby pulsating the supply air and improving the air supply efficiency. It aims to improve. (The exhaust manifold 1'illustrated in FIG. 11 can be applied.) However, in this case, when the supercharger T2 is stopped, the exhaust gas from the cylinders C4 to C5 that should be sent to the supercharger T1. Since the outlet is lost, a structure for guiding these exhausts to the supercharger T2 is required. Therefore, as described above, both turbochargers T1 and T2
When a communication passage R is formed between the inlets of the two turbochargers and the supercharger is operated by two units, it is closed to introduce the exhaust gas to each supercharger independently, and only one unit is operated. , It is configured to open.

The mounting structure of each of the turbochargers T1 and T2 and the disposition structure of the exhaust control valve will be specifically described with reference to FIG.
Each of the superchargers T1 and T2 has the same structure as that of FIGS.
The exhaust control valve 12 is attached to each of the spacers 2 and the spacers 2 to which the supercharger T2 is attached. In order to form the communication passage R, the communication branch pipe 15 is provided between the lower end of each spacer 2 and each exhaust outlet 1d of the exhaust manifold 1.
And a communication pipe 16 is interposed between both branch pipes 15 for communication. Then, an exhaust control valve 17 is provided in the communication pipe 16.
Is installed internally. The opening and closing of the exhaust control valves 12 and 17 will be described. When the supercharger T2 is stopped, the exhaust control valve 12 is closed, and at the same time, the exhaust control valve 17 is opened, and the exhaust from the cylinders C4 to C6 is connected to the communication pipe 16 Through the supercharger T1. When the exhaust control valve 12 is opened during operation of both the superchargers T1 and T2, the exhaust control valve 17 is closed in conjunction with this, and the exhaust from the cylinders C1 to C3 is transferred to the supercharger T1. Exhaust gas from the cylinders C4 to C6 is independently introduced into the supercharger T2.

When high-temperature exhaust gas flows in the communication pipe 16 and the distance between the communication branch pipes 15 is constant, when the communication pipe 16 itself is stretched due to high temperature, the communication pipe 1
6 and the communication branch pipe 15 may be damaged. Therefore, as described above, the connecting portion of the exhaust outlet pipes 3 and 3 to the exhaust outlet end Tb of the turbine T of each turbocharger T1 and T2 is made into a seal ring shape so that it can slide, similarly to the communication pipe. The expansion pipe 16c is provided between the communication main pipe 16a and the communication valve pipe 16b in which the exhaust control valve 17 is installed.
The expansion tube 16c is made of, for example, bellows-shaped heat resistant rubber,
Expansion pipe joints 16d and 16d are provided at both ends thereof so as to be flange-connectable to the communication main pipe 16a and the communication valve pipe 16b. The expandable pipe 16c contracts as the communication main pipe 16a and the communication valve pipe 16b are stretched due to high heat, and the damage of the communication main pipe 16a and the communication valve pipe 16b can be avoided.

[0036]

As described above, the present invention has the following advantages. That is, since it is configured as in claim 1, there is no need to form a mounting structure for the supercharger in the exhaust manifold, the shape of the exhaust manifold can be unified, and the processing cost can be reduced. Then, by changing the mounting direction of the spacer to which the supercharger is attached, the exhaust outlets are arranged as twin turbos facing each other (the exhaust bend is shared and the cost is low). It can be mounted on either side, the shape can be unified, and the cost is low. In addition, even if the structure of the supercharger is changed, the exhaust manifold may have the same shape, and the shape of only the spacer may be changed. This also contributes to cost reduction.

Further, since the waste gate passage is formed separately from the supercharger, it is not necessary to construct a supercharger having a built-in waste gate, which contributes to cost reduction. Since the waste gate passage is separate from the supercharger, the valve opening amount of the passage can be freely set regardless of the control of the exhaust gas introduction amount of the supercharger. Further, by disposing the waste gate passage between the exhaust outlet of the exhaust manifold and the exhaust bend, the support member that was conventionally required to support the exhaust bend above the exhaust manifold is not required. .

Then, in the internal combustion engine capable of switching between the state of operating only one supercharger and the state of operating two superchargers,
Since it is configured as in claim 3, in addition to the effect of claim 1, the exhaust control valve is attached in the spacer,
In the exhaust manifold, there is no need to provide a structure for attaching to the supercharger or a structure for attaching an exhaust control valve, and the shape of the exhaust manifold can be unified, which contributes to cost reduction. Further, it is possible to easily change to a normal internal combustion engine simply by removing the exhaust control valve from the spacer.

Furthermore, a water-cooled exhaust manifold may be provided in accordance with claim 4.
By using a welded assembly structure as shown in the figure, it is not necessary to construct a mold such as a complicated core unlike the one-casting type exhaust manifold. You can

[Brief description of drawings]

FIG. 1 is a partial front sectional view of a pipe portion of an exhaust manifold 1 of an internal combustion engine having a structure in which superchargers T1 and T2 are attached via a spacer 2.

FIG. 2 is a partial side sectional view of the supercharger T1 mounting portion as seen from the left side in FIG.

FIG. 3 is a partial side sectional view of the supercharger T2 mounting portion as seen from the left side in FIG.

FIG. 4 is a partial front cross-sectional view of an exhaust manifold 1 piping portion of an internal combustion engine having a structure in which a waste gate pipe 9 is provided.

FIG. 5 is a partial side cross-sectional view of an exhaust manifold 1 piping portion of an internal combustion engine having a structure provided with a waste gate pipe 9 ′.

[FIG. 6] Both turbochargers T1
FIG. 3 is a partial front cross-sectional view of a pipe portion of an exhaust manifold 1 of an internal combustion engine of a sequential control system that has an exhaust manifold 1 of a type that supplies T2 and can stop a supercharger T2.

FIG. 7 is a partial side sectional view of the supercharger T2 mounting portion as seen from the left in FIG.

8 is an exhaust / air supply system diagram in the structure shown in FIGS. 6 and 7. FIG.

[Fig. 9] The inside is divided into two parts, and the exhaust is independent of both turbochargers T.
1 ・ T2 has an exhaust manifold 1 of the type that supplies
It is a front partial cross-sectional view of the exhaust manifold 1 piping portion of the internal combustion engine of the sequential control system in which the supercharger T2 can be stopped.

10 is an exhaust / air supply system diagram in the structure shown in FIG. 9. FIG.

FIG. 11 is a plan partial cross-sectional view showing a water-cooled exhaust manifold 1 ′ having a welded assembly structure.

FIG. 12 is a plan partial cross-sectional view showing a water-cooled exhaust manifold 1 ″ having a welded assembly structure.

[Explanation of symbols]

 T1 ・ T2 Supercharger T Turbine B Blower 1 Exhaust manifold 1a Outer cover 1b ・ 1b 'Exhaust main pipe 1c Exhaust introduction pipe 1d Exhaust outlet 1e Wastegate introduction opening 2 Spacer 3 Exhaust outlet pipe 4/4' Exhaust bend 4 ' a waste gate outlet pipe part 6 air supply connecting pipe 9 waste gate pipe 9a waste gate passage 10 waste gate valve 11 actuator 12 exhaust control valve 13 air supply control valve 14 air supply relief valve 15 communication branch pipe 16 communication pipe 16a communication main pipe 16b Communication valve pipe 16c Expansion pipe 16d Expansion pipe joint 17 Exhaust control valve 1'Exhaust manifold 18 External cover 19/19 'Exhaust introduction pipe 20 Exhaust branch pipe 21 Exhaust confluent pipe 21a Exhaust flange part 1 "Exhaust manifold 18' External cover 20 'Exhaust branch pipe 21' Exhaust merging pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02B 37/007 F02B 37/00 301C 37/00 301H (72) Inventor Takashi Saeki Kita, Osaka City, Osaka Prefecture 1-32, Chayamachi, Yanma Diesel Co., Ltd. (72) Inventor, Moto Haeda 1-32, Chayamachi, Kita-ku, Osaka City, Osaka Prefecture

Claims (4)

[Claims] 1. Forming two outlets in an exhaust manifold,
An internal combustion engine having a structure in which each outlet is connected to two independent turbochargers, the rotation axes of both turbochargers are parallel to the longitudinal direction of the exhaust manifold, and the exhaust outlets of both turbochargers face each other. In the structure in which both superchargers are arranged in the upper part of the exhaust manifold, a spacer also serving as an exhaust communication pipe is provided between the exhaust outlet formed at the upper end of the exhaust manifold and the supercharger inlet, The exhaust system structure of the internal combustion engine is characterized in that the spacer can be mounted on any turbocharger by changing the mounting direction. 2. Forming two outlets in the exhaust manifold,
An internal combustion engine having a structure in which each outlet is connected to two independent turbochargers, the rotation axes of both turbochargers are parallel to the longitudinal direction of the exhaust manifold, and the exhaust outlets of both turbochargers face each other. In a structure in which both turbochargers are arranged above the exhaust manifold and both exhaust outlets are connected to one exhaust bend, a wastegate passage separate from the supercharger is provided from the exhaust manifold to the exhaust bend. An exhaust system structure of an internal combustion engine characterized by being interposed. 3. The exhaust system structure for an internal combustion engine according to claim 1, wherein a control system capable of switching between a state in which only one supercharger is in operation and a state in which both superchargers are in operation is employed. In the exhaust system structure of an internal combustion engine, an exhaust control valve is provided only in one of the two spacers to which each supercharger is attached. 4. A water-cooled type in which an exhaust passage interposed between a cylinder head of an internal combustion engine and a supercharger is covered with an outer cover, and a space between the outer cover and the exhaust passage serves as a cooling water chamber. An exhaust manifold, wherein the outer cover and the exhaust passage are separate bodies, and the exhaust passage is formed by connecting an exhaust introduction pipe, an exhaust branch pipe, and an exhaust merging pipe, which are separate bodies, and each connecting portion. Is an exhaust system structure of an internal combustion engine, which is provided with a water-cooled exhaust manifold constructed by welding to maintain watertightness.